Built up strip mill guide of composite copper alloy layers

ABSTRACT

A STRIP MILL GUIDE SUCH AS POSITIONED BETWEEN THE STANDS OF ROLLS IN A ROLLING MILL AND PARTICULARLY ADJACENT THE STANDS OF ROLLS SO AS TO SUITABLY GUIDE THE TRAVELING STRIP RELATIVE THERETO IS DISCLOSED HAVING AN ELONGATED CENTRAL AREA BUILT UP WITH A TIN LEAD COPPER ALLOY CHARACTERIZED BY ITS ABILITY TO PREVENT DENTRIFIC GRAIN STRUC-   TURE FORMING IN THE GUIDE BODY AND THEREBY STRENGTHEN THE SAME SO AS TO PROVIDE A GREATLY INCREASED LIFE.

Jung 29, 1971 CAKES 3,589,876

BUILT UP STRIP MILL GUIDE OF COMPOSITE COPPER ALLOY LAYERS Filed Feb. 28, 1969 IN VENTOR.

Grani A. Oakes AT; OPNEY United States Patent Oflice Patented June 29, 1971 U.S. Cl. 29-199 4 Claims ABSTRACT OF THE DISCLOSURE A strip mill guide such as positioned between the stands of rolls in a rolling mill and particularly adjacent the stands of rolls so as to suitably guide the traveling" 'strip relative thereto is disclosed having an elongated central area built up with a tin lead copper alloy characterized by its ability to prevent dendritic grain structure forming in the guide body and thereby strengthen the same so as to provide a greatly increased life.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to strip mill guides of the type normally employed to guide the edges of strip between the stands of a rolling mill.

(2) Description of the prior art Prior structures of this type are those found in my Pats. 3,289,457 and 3,289,292 in which built up strip mill guide and the method of making the same are disclosed. The inventions set forth in these patents have been widely commercially adopted by the steel industry and such built up strip mill guides have been reworked according to the inventions and found'to progessively lose their desirable qualities through the reworking operations. The present invention overcomes the difficulties by changing the tin and lead content of the alloying material used in the built up guide to a point where the metal of the guide itself is saturated with the tin and lead sufiiciently to prevent dendritic grain structure from occurring. Strip mill guides formed in accordance with the present invention may be reworked and found to be improved in their life span characteristics and wearing ability.

SUMMARY OF THE INVENTION A built up strip mill guide is normally formed of a bronze alloy which is relatively softer than the steel directed to the roll stands of the strip mill and is so positioned that the edges of the strip steel being guided thereby engage the longitudinal center sections of the guides themselves. By building up the elongated central wear section of the strip mill guide with a copper alloy having a relatively high percentage of tin and lead, a guide is provided which improves in the rebuilding operation particularly with respect to the grain structure of the guide. In the past the grain structure has shown abnormal dendritic growth upon attempts to rebuild the guide structures.

The present invention not only improves the original built up guide particularly with respect to wear characteristics and grain structure but permits the guide to be rebuilt periodically to replace the worn away metal and without adversely affecting the grain structure.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a built up strip mill guide formed in accordance with this invention.

FIG. 2 is a perspective view of a strip mill guide during formation of the built up wearing surface thereof.

FIG. 3 is an enlarged cross section on line 3-3 of FIG. 2.

FIG. 4 is an enlarged cross section on line 4-4 of FIG. 2.

FIG. 5 is an enlarged cross section on line 55 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT By referring to the drawings and FIG. 1 in particular it will be seen that a strip mill guide has been disclosed which is of conventional size and shape and in the example chosen for illustration the guide is approximately 33 inches long x 3 /2 inches in width and one inch in thickness. It has a T head at one end, the guide body being indicated by the numeral 10, and the T head being indicated by the numeral 11. The T head is formed with a projecting extension 12 of lesser height than the remainder of the head 11 of the strip mill guides so that it will fit beneath a mounting member in a conventional mounting means positioned along side the pass line of a strip mill, for example, and adjacent a stand of reducing rolls therein.

The opposite end of the strip mill guide 10 has an angular end portions 13 and 14 which angle toward one another and terminate with a relatively narrow end portion 15.

As seen in FIG. 1 of the drawings the strip mill guide is in condition for installation in the guide means of a strip mill.

By referring to FIG. 2 of the drawings, the same strip mill guide will be seen in perspective elevation with a longitudinally extending groove 16 therein and which groove 16 extends from the end portion 15 to the T head portion 11 and the projecting extension 12 as heretofore referred to. The groove 16 is formed in the strip mill guide body 10 and filled in with a nickel tin lead copper alloy as seen in FIG. 2 and indicated by the numeral 17.

The alloy 17 is provided by a welding rod 18 which is shown in FIG. 2 of the drawings in welding position flowing the metal thereof into the groove 16. An electric arc torch 19 is used as will be understood by those skilled in the art. The conventional strip mill guide 10 is copper, 10% tin and 10% lead and has a normal fine grain structure which forms a suitable supporting body for the built up section formed therein by this invention. The alloy of the rod 18 shown flowing into the groove 16 is high in lead and tin and preferably includes a small amount of nickel. An alloy consisting of 64% copper, 20% lead, 15% tin and 1% nickel is suitable. The lead may be present in the alloy in percentages running from 11% to 45%. The tin may be from 11% to 30% of the alloy and the balance copper except for the nickel which can be present in percentages from 1% and under some conditions may be eliminated, such as where the lead and tin content are very high.

Those skilled in the art will observe that the heat necessary to weld the metal in the groove 16 is sufficient to remove or relocate the tin and lead of the strip mill guide 10 whereupon dendritic growth of the grain structure occurs and which results in an unsatisfactory strip mill guide as it becomes brittle, easily broken and subject of rapid wear. By utilizing the alloy disclosed here in which is high in tin and lead and preferably has nickel as a stabilizer, the heretofore believed normal migration of the tin and lead is prevented and no dendritic grain structure growth occurs.

Those skilled in the art will recognize that the primary reason for the dendritic grain growth in a bronze alloy strip mill guide is the migration of the lead and tin constituents thereof to the last heat affected zone which comprises the areas in the guide body away from the weld area in which the alloy 17 is being deposited. In other words, the lead and tin constituents of the bronze alloy of the strip mill guide body 10 move into the areas away from the weld towards the center of the guide leaving the areas adjacent the weld relative- 1y free of lead and tin and thus accelerating the dendritic grain structure which leads to the failure of the strip mill guide as it becomes brittle, easily broken and is subject to rapid wear. By utilizing the alloy hereinbefore specified in the build up Welding and rewelding of the critical area of the guide, saturation of the guide metal by the migration of the lead and tin of the alloy inhibit the dendritic growth and thus maintain the strip mill guide in desirable condition.

The importance of the present invention will be recognized by the fact that the strip mill guides can be rebuilt by rewelding a number of times as the initial wearing away of the first deposited weld area makes it possible to reweld and rebuild the guide while maintaining the alloy of the guide in its normal non-brittle state.

It will thus be seen that the built up strip mill guide disclosed herein comprises an improvement in the art and makes possible the reuse by rebuilding of strip mill guides and permits their continuous use through a series of rebuilding operations, none of which adversely affect the grain structure of the original guide body.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent 4 to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.

I claim:

1. A guide for traveling strips in a strip mill and the like comprising an elongated member consisting essentially of 80% copper, 10% lead and 10% tin and having a longitudinally extending wear area of an alloy consisting essentially of copper in an amount between and 77%, lead in an amount between 11% and and tin in an amount between 11% and 30%, said wear area being integrally welded to said guide.

2. The guide set forth in claiml and wherein the copper amounts to the lead to 20% and the tin to 15%.

3. The guide of claim 2 wherein the copper is reduced to 64% and nickel is present in the amount of 1%.

4. The guide of claim 1 and wherein nickel is included in an amount between 1% and 4% of the total alloy.

References Cited UNITED STATES PATENTS HYLAND BIZOT, Primary Examiner 

